Summary translation

Causes of variation in productivity, mortality rate and cannibalism rate in different huosing systems revealed a strong effect of genotype and in brown birds differences may occur between beak-trimmed and intact hens. Diet x genotype interactions seem preferably to influence health criteria, whereas genotypes tend to react similar what concerns production characteristics. The content of insoluble fibre in the diet may influence feather-pecking behaviour, and oats has been shown to decrease the risk of feather-pecking whereas wheat had the opposite effect. Genotypes were found to behave significant differently to variations in the diet’s methionine content, and methionine supplementation preferably improved health criteria and less production in number of eggs.